Tape record repeater



Dec. 20, 1938. I w. ANDRUS TAPE RECORD REPEATER Filed Aug. 18-, 1936 as a 7'0 TRAN M/TTER 3 a a n :.:w W 5 1 wi k -41 fm v 6 AMPLIFIER INVENTOR, WILL/AM LE L AND ANDRUS ATTORNEYS.

Patented Dec. 20, 1938 UNITED STATES PATENT OFFICE TAPE RECORD REPEATER William Leland Andrus, San Francisco, Calif.

Application August 18, 1936, Serial No. 96,585

10 Claims. (Cl. 178-70) This invention relates to repeaters for telegraph messages recorded on tape, as, for example, by a syphon recorder.

Among the objects of this invention are: To

provide a simple and effective method of retransmitting telegraph messages which have been recorded as a zigzag line upon a tape of insulating material, such as paper or Cellophane; to provide a tape actuated repeater which may be used to retransmit either Wire or radio-telegraph signals; to provide a repeater which does not introduce the complications of photocells; to provide a repeater which will not send out false signals in case of a break in the record line; and to provide a repeater wherein record tape may be conserved by successively recording and reproducing messages upon and from both sides of the tape.

My invention possesses numerous other objects and features of advantage, some of which, to-

gether with the foregoing, will be set forth in the following description of specific apparatus embodying and utilizing my novel method. It is therefore to be understood that my method is applicable to other apparatus, and that I do not limit myself, in any way, to the apparatus of the present application, as I may adopt various other apparatus embodiments, utilizing the method, within the scope of the appended claims.

Referring to the drawing:

Figure 1 is an enlarged plan view of the receiver and a portion of the tape, the clockwork driving mechanism being omitted.

Figure 2 is a longitudinal sectional View of the apparatus shown in Figure 1, the plane of section being indicated by the dot and dash line 2-2 of Figure 1.

Figure 3 is a transverse sectional view, the plane of section being indicated by the dot and dash line 3-3 of Figure 2.

Figure 4 is a schematic diagram showing a preferred method of connecting the repeater of my invention.

The method of recording telegraph messages by syphon recorder has been used for many years on cable lines, and is also employed in radio telegraph service. In th s method of recording the record is a substantially continuous trace upon a paper tape which is continuously moved through the recorder, and the receiver comprises a pen which is deflected across the tape in accordance to the signals. Where the usual Morse or Continental Morse code is used. the pen moves to one side of its median position to transm t the dots and dashes and to the other side of. its median position to indicate the spaces between the electrical impulses. comes out as a substantially continuous zigzag line, whose peaks represent the characters transmitted, a relatively long peak or plateau indieating a dash, While a shorter peak indicates a dot. While the trace is substantially continuous, the type of pen used does not always work perfectly, and there may he breaks in the trace, these breaks usually coming in the sloping sides of the service, where the message must be retransmitted either from a relay point to its ultimate destination, or back to its point of origin for check. Where mechanical transmission is used, this means that the message must be read by an operator who, with a Wheatstone or Kleinschmidt perforator, retranscribes the message as perforations on a new tape, which is utilized to operate the transmitter. This involves the intervention of the operator, with consequent possible source of error, to say nothing of the time and expense involved.

In accordance with my invention, the receiver tape itself is utilized to retransmit the message, thus avoiding the labor and possible sources of error involved in its retranscription. In utilizing the invention, the recording differs from standard practice only in the use of an electrically conducting means for forming the trace, the sensitivity of the receiver and the recorder being such that all received impulses impart to the recorder pen the maximum deviation of which it is capable, so that all impulses, whether short or long, result in peaks of the same height. This is the customary adjustment, particularly in radio practice.

Considered broadly, the method of my invention comprises using the conductivity of the trace to complete the circuit. In order to accomplish this, a contact is made with the moving tape in such manner as to cover an appreciable area of the trace, preferably on both sides of the point which is being transcribed. A separate electrical contact is made with the tape on the line representing the maximum deviation of the trace from its median position, usually, although not necessarily, on the lineof the peaks which represent The record, therefore,

the dots and dashes. This latter contact is made with a point of elementary area; the source of potential and the actuating circuit of a relay are connected to the contacts, and the making and breaking of the circuit, including a short length of the trace, accomplishes the keying of the transmitter through the relay.

Considering a preferred form of the invention in greater detail, the record tape I, bearing the trace 2 of the record in conducting ink, is moved continuously by a friction roller 3. The roller is mounted upon a shaft 5, which is driven by a conventional clockwork or electric motor. This motor is not shown, since it is conventional in form and such drives are well known in the art.

Several types of conducting ink for forming the trace 2 are well known in the art. Ordinary India drawing ink is satisfactory and works well in the syphon pen if slightly diluted, e. g., with ammonia. Various metallic inks may also be used, but in general I have found the India ink to be entirely satisfactory and prefer to use it since it is readily obtainable and flows freely in the syphon pen.

Secured to the frame 6 of the receiver mechanism is a trough I, which may be made of either conducting or insulating material, although I prefer to make it of metal and polish it highly so as to offer a minimum of friction to the tape I as it passes through.

Also mounted on the frame 6 is a supporting stud 8, which projects over the moving tape, and whose end is slit to hold a leaf spring III, the end of the spring projecting forward to lie within the trough I, and press down upon the tape. This spring may itself be the contact, but I prefer to make the actual contact with the tape by means of a polished metal contact shoe II, against which the spring presses and which is held in place by pins or dowels I2 which pass loosely through holes I3 in the spring. This arrangement allows the shoe to press firmly against a considerable length of the tape, making contact with the trace.

The contact point I5 bears against the tape on a line with the maximum deviation of the trace from its median position, passing through an opening I6 in the shoe. This opening may either be a hole, as shown, or a notch in the edge, as may be convenient. The point I5 makes contact with an elementary length of the trace 2, wherever this trace reaches maximum deviation in its proper direction. Preferably, the point should be accurately guided and carefully adjusted. In the preferred form of the device shown this is made possible by a bridge I I, preferably of insulated material, over the trough I. This bridge carries a bushing I8 which guides the point, the latter being urged against the tape by means of a spring 20 which bears against a collar 2| on the point and against an adjusting screw 22 supported by a bracket 23. Other manners of accomplishing the same purpose will at once suggest themselves to those skilled in the art.

In practice, connections 25 and 26 are made to the point I 5 and the shoe I I respectively, through the bracket 23 and the stud 8 which supports the spring I 0. As the tape is carried forward, the circuit between the shoe and the point is completed by the conducting ink whenever the point I5 rests upon the trace. This will occur even though there may be a break in the sloping sides of the peaks since the shoe contacts the trace on both sides of the point and there is always a portion of the horizontal peak in contact with the shoe, and the current can flow in either direction from the point thereto.

Various types of connection may be used to utilize the contact thus made and cause it to complete a telegraph circuit. A preferred arrangement is shown diagrammatically in Figure 4, wherein a source of alternating potential 21 (which may conveniently be an electrically driven tuning fork but which may be any conventional type of generator or oscillator) is connected between the shoe II and ground. A connection 25 leads to the input circuit of a vacuum tube 28, this circuit in the present instance comprising a high resistance potentiometer 30 connected between the grid of this tube and the filament, which is grounded through a biasing resistor 3|. The output circuit of the tube feeds through an amplifier 32, whose final stage includes an overbiased tube or other form of detector which rectifies the amplified alternating current from the source 2! to operate a magnetic relay 33. This relay may be used to key any conventional radio or wire circuit.

That many modifications may be made in this hookup is obvious. I prefer to use the amplifier 32, because of increased sensitivity gained thereby and consequent greater positiveness of action, but I have found that it is not necessary, and that it is possible to operate a relay directly from the tube 28, by biasing the latter to cut-off. Under these circumstances the source 21 may supply either direct or alternating current. It is further obviously possible to have the source 21 a master oscillator operated at radio-frequency and to feed directly into a radio transmitter through the proper amplifier circuits without the intervention of the relay 33, the keying thus being accomplished directly by the trace 2.

It is also clear that the device may readily be operated if the contact I5 is alined with the off phase of the trace instead of the on phase, since all that is necessary in this case is to reverse the phase of the connection somewhere in the circuit, as, for example, by connecting the output circuit 35 of the relay to the back instead of the front contact, or by using grid leak detection in the amplifier 32 instead of plate detection.

It should be noted that both contacts are made on the same side of the tape. For this reason there is no need that the tape itself be rendered conductive by the ink; electrolitic conduction is not relied upon, as the ink may be perfectly dry, the message being repeated many hours after its original reception. This also permits the tape being turned over and a second record made upon the opposite side. This results not only in the saving in tape, which may be relatively unimportant, but also in a great reduction in the storage space required for the tapes after transmission, since it is ordinarily required that the records be preserved for a greater or less length of time.

I claim:

1. The method of retransmitting received telegraph signals, which comprises the steps of recording said signals on insulating tape with conducting ink as a substantially continuous line, continuously moving said tape, electrically contacting said line at two positions longitudinally spaced therealong, making a separate electrical contact with an elementary length of said line between said spaced positions and corresponding to a predetermined phase of the received signal, applying an electrical potential between the points of contact on said line, and utilizing the currents flowing as a result of said potential to initiate the repeated signal.

2. The method of retransmitting received telegraph signals, which comprises the steps of recording said signals on insulating tape with conducting ink as a substantially continuous line having substantially uniform deviations from a mean position relative to the tape representing the on and off phases of the received signal, continuously moving said tape in a direction parallel to said mean position, electrically contacting said line at two positions longitudinally spaced therealong, electrically contacting an elementary area of the moving tape at a position corresponding to the deviation of said line at one of said signal phases and between two said first-mentioned positions, applying an electrical potential between the positions where electrical contact is made, and utilizing currents flowing through the ink when both areas of contact include said line to initiate the repeated signal.

3. The method of retransmitting received telegraph signals, which comprises the steps of recording said signals on insulating tape with conducting ink as a substantially continuous line having substantially uniform deviations from a mean position relative to the tape representing the on and off phases of the received signal, continuously moving said tape in a direction parallel to said mean position, electrically contacting said line at two positions longitudinally spaced therealong, electrically contacting an elementary area of the moving tape at a position corresponding to the deviation of said line at one of said signal phases and between two said first-mentioned positions, applying an alternating electrical potential between the positions where electrical contact is made, amplifying the currents flowing through the ink when both areas of contact include said line, and utilizing the amplified currents to initiate the repeated signal.

4. Apparatus for retransmitting tape-recorded telegraph messages of the type produced by a syphon recorder, which comprises means for moving said tape, a contact shoe bearing on said tape of sufiicient area to contact the record thereon irrespective of the character momentarily being traversed, a contact point of elementary length mounted adjacent said shoe and insulated therefrom and aligned with the position of maximum deviation of said record from its median position, means for applying a potential between said contact point and shoe, and means actuated by currents flowing as a result of said potential for operating a transmitter.

5. Apparatus for retransmitting tape-recorded telegraph messages of the type produced by a syphon recorder, which comprises means for moving said tape, a contact shoe bearing on said tape of suificient area to contact the record thereon irrespective of the character momentarily being traversed, a contact point of elementary length mounted adjacent said shoe and insulated therefrom and aligned with the position of maximum deviation of said record from its median position, an alternating potential source and an electron relay having an actuating circuit, said source and circuit being connected in series with said contact point and shoe, and an electromagnetic relay connected for actuation by said electron relay for transmitting the signals.

6. In combination with a tape having a telegraph message of syphon-recorded type thereon in conducting ink, a repeating apparatus comprising means for continuously moving said tape, means for electrically contacting the moving tape and the record thereon on both sides of a reproducing position, a contacting point aligned with the position of maximum deviation of said record from its median position, and a potential source and keying circuit connected in series with said contacting means and point.

7. Apparatus for retransmitting tape-recorded telegraph messages of the type produced by a syphon recorder, which comprises means for moving said tape, a contact shoe bearing on said tape of suificient area to contact the record thereon irrespective of the character momentarily being traversed, an opening in said contact shoe aligned with the position of maximum deviation of the record from its median position, a contact point insulated from said shoe and bearing on said tape through said opening, and a keying circuit connected between said contact point and shoe.

8. The method of repeating tape-recorded telegraph messages, which comprises the steps of forming a trace on the tape as a substantially continuous line of conducting ink, said line deviating a substantially constant distance on one side of it median position when the transmitting circuit is closed and on the opposite side of said position when said circuit is open, continuously moving said tape in a direction parallel to said median position, contacting a relatively great length of said trace passing an electrical current through those portions of the record trace corresponding to maximum deviation of said'line in one direction, and utilizing said current to initiate the retransmitted signal.

9. Apparatus for retransmitting tape-recorded telegraph messages of the type produced by a syphon recorder, which comprises means for moving said tape, a contact shoe bearing on said tape of sufficient area to contact the record thereon irrespective of the character momentarily being traversed, an opening in said contact shoe aligned with the position of maximum deviation of the record from its median position, a contact point insulated from said shoe and bearing on said tape through said opening, and a keying circuit of constant resistance connected between said contact point and shoe.

10. The method of repeating tape-recorded telegraph messages, which comprises the steps of forming a trace on the tape as a substantially continuous line of conducting ink, said line deviat--- ing a substantially constant distance on one side of its median position when the transmitting circuit is closed and on the opposite side of said position when said circuit is open, continuously moving said tape in a direction parallel to said median position, contacting a relatively great length of said trace, passing an electrical current through a uniform length of those portions of the record trace corresponding to maximum deviation of said line in one direction, and utilizing said current to initiate the retransmitted signal.

WILLIAM LELAND ANDRUS. 

